WASHINGTON (AP) – A major Greenland glacier that was one of the fastest shrinking ice and snow masses on Earth is growing again, a new NASA study finds.
Around 2012, retreating about 1.8 miles and thinning was nearly 130 feet annually. But it started growing again at about the same rate in the past two years, according to a study in Monday's Nature Geoscience. Study authors and outside scientists think this is temporary
"That was kind of a surprise. We've got used to a runaway system," said Geological Survey of Denmark and Greenland ice and climate scientist Jason Box. "The good news is that it's a reminder that it's not necessarily going to be. But it's going." Box, who wasn't part of the study, said Jakobshavn is "arguably the most important Greenland glacier because it discharges." The most ice in the northern hemisphere. For all of Greenland, it is king. " Melting Greenland (OMG) project. Khazendar and colleagues say this coincides with the North Atlantic Oscillation ̵
The water in Disko Bay, where Jakobshavn hits the ocean, is about 3.6 degrees cooler (2 degrees Celsius) than a few years ago, study authors said.
While this is "good news" on a temporary basis, this is bad news on the long term because it According to NASA, climate scientist Josh Willis, a study co-author. Over the decades the water has been and will be warming from man-made climate change, he said, noting that about 90 percent of the heat trapped by greenhouse gases goes into the oceans.
"In the long run we'll probably said, "Willis said.
Think of the ocean temperatures near Greenland like an escalator that's rising slowly from global warming, Khazendar said. But the natural North Atlantic Oscillation is sometimes jumping down a few steps or jumping up a few steps. The water can get cooler and have effects, but in the long run it is getting warmer and the melting will be worse, he said.
Four outside scientists said the study and results make sense. Ian Joughin, who was not part of the study and predicted such a change seven years ago, said it would be a "grave mistake" to interpret the latest data as contradicting climate change science.
What's happening, Joughin said, is "to a large extent, a temporary blip. Downturns do occur in the stock market, but overall the long term trajectory is up. This is really the same thing."
Follow Seth Borenstein on Twitter: